1. Field of the Invention
The invention relates to a leakproof and fireproof tubing, and in particular to a leakproof and fireproof tubing including an inner tube, an outer tube surrounding and coaxial with the inner tube, and a heater and a foil located therebetween.
2. Description of the Related Art
In semiconductor processes, a variety of chemical gases or liquids are commonly used. Therefore, it is necessary to have individual transmission systems for conveying the various chemical gases or liquids. Designs of the various transmission systems depend on the properties of the transmitted chemical gases or liquids.
In general, a gas transmission system is used to transmit a gas from a gas cylinder to processing equipment via a tubing and valves. The gas cylinder is usually positioned in a gas cabinet.
Currently, double coaxial tubes have been adopted to make a tubing used for transmitting corrosive, combustible, toxic and explosive chemical fluids. The double coaxial tubes, serving as a tubing, consist of an inner tube and an outer tube having different diameters, wherein the inner tube is positioned inside the outer tube. The inner tube is mainly used to transmit the above-mentioned dangerous chemical fluids while the outer tube is used to protect the inner tube. However, if the tubing does not have a heater installed, the system is easily congested when transporting a number of easily-congealed chemical fluids.
Another tubing is designed with a heater as shown in FIG. 1. In FIG. 1, a tube 10 is surrounded by a heater 12, and then enclosed by an insulator 14. Due to the large volume of the insulator 14, it is unnecessary to additionally install an outer tube. Even though this design can prevent chemical fluids from congealing, no method is provided to prevent chemical fluid leakage. If the tube 10 or the heater 12 is broken, a chemical fluid leakage and/or fire on the transmission system due to a short circuit on the heater can easily occur.